Data centers may be configured to supply cold air to server racks bearing information technology (IT) devices from the under floor space through air transfer grilles (grilles) have been used. In the above-described data center, there has been a tendency for the calorific value of each of the server racks to increase with an increase in the heat generation density of the IT devices borne on the server racks. Consequently, a hotspot or the like occurs due to the infiltration of exhaust from the IT devices.
Here, the air flows that are observed in the data center will be described with reference to FIG. 17. As shown in FIG. 17, the air flows that are observed in the data center include the flow of air that is blown out from an air conditioner and that is sucked into the rack (see I shown in FIG. 17), the flow of air that is blown out from the air conditioner and that is sucked into the air conditioner (see II shown in FIG. 17), the flow of air that is discharged from the rack and that is sucked into the air conditioner (see III shown in FIG. 17), and the flow of air that is discharged from the rack and that is sucked into the rack (see IV shown in FIG. 17).
When a large volume of air is exhausted from the rack and is passed to a path leading to the rack so that the air is sucked into the rack 21, the hotspot occurs due to the infiltration of exhaust from the IT devices. The method of reducing the temperature of air sent from an air conditioner and/or the method of adding facilities to the data center have been available as the method of reducing the above-described hotspot (see Japanese Laid-open Patent Publication No. 2008-185271, Japanese Laid-open Patent Publication No. 2006-046671, and Japanese Laid-open Patent Publication No. 2002-6992). For example, the method of adding an air conditioning system to reduce the temperature of air sent from an air conditioner to reduce the temperature of the entire room and/or the method of adding a partition to the side part of a row of racks and/or the upper part of the rack has been used to reduce the hotspot occurring due to the exhaust infiltration.
Incidentally, since the above-described method of reducing the temperature of the air sent from the air conditioner and/or the above-described method of adding the facility to the data center allows for reducing the air temperature, a large amount of power is consumed. Further, since providing the additional facilities costs money, it has been difficult to cool the racks with efficiency.